Method for cleaning the interior of television tubes for reconditioning



W. HOLT May 22, 1962 METHOD FOR CLEANING THE INTERIOR OF TELEVISIO TUBES FOR RECONDITIONING Filed May 23, 1960 FIG.4

INVEN TOR. 14044 I444 H01 7' MW United States Patent Oii ice 3,035,909 Patented May 22, 1962 3,035,909 METHOD FOR CLEANING THE INTERIGR F TELEVISION TUBES FOR RECONDITIONING William Holt, 701 Passaic Ave., Arlington, N.J., assignor of fifty percent to Andrew F. Stanier, Passaic, NJ. Filed May 23, 1960, Ser. No. 31,152 1 Claim. (Cl. 51-617) This invention relates to the grinding of television tube interiors and specifically to apparatus and method for removing all foreign and deposited material from the intenor of television tube envelopes.

In the reconditioning of television tubes it is customary to cut the gun from the envelope of the television tube and thereafter remove the phosphor and any other material that may have been deposited on the interior surfaces of the tube. Presently known techniques for this purpose employ strong acids which are not only dangerous from the standpoint of handling and working conditions, but also produce an undesirable mark within the tube which may be seen after the new phosphor has been applied thereto. The undesirable mark is the result of the unequal etching of the interior of the tube by the acid due to the fact that certain portions of the tube glass are harder than others. This unequal hardness is brought about by the chilling of the glass during its manufacture and the undesirable markings are known as chill or cord marks.

Accordingly, it is an object of the present invention to provide an apparatus and method for grinding the interior of television tube envelopes in a manner which will render them highly satisfactory for reuse.

Another object of the present invention is to provide a television tube grinding apparatus which will not require the use of strong acids.

A further object of the present invention is to provide a television tube grinding apparatus which will not show chill marks when the tube is completely reconditioned.

An object of the present invention is to provide a television tube grinding apparatus which will provide an excellent surface to receive the phosphor.

An object of the present invention is to provide a television tube grinding apparatus which will be rapid and economical in its operation.

A feature of the present invention is its use of a plurality of round marbles or pebbles together with abrasives placed on the inside of the television tube face for removing any phosphor or other materials thereon.

Another feature of the present invention is its use of a table actuated by a crank mechanism for agitating the abrasive material Within the television tubes.

Another feature of the present invention is its method of charging the interior of the television tube with the pebbles without damaging the face of the tube.

The invention consists of the construction, combination, and arrangement of parts, as herein illustrated, described and claimed.

in the accompanying drawing, forming a part hereof is illustrated one form of embodiment of the invention and in which:

FIGURE 1 is a view in longitudinal section of a television tube envelope showing the manner in which a charge of small round members or marbles may be inserted therein.

FiGURE 2 is a view similar to FIGURE 1 showing the television tube following the placement therein of the round marbles and an abrasive material.

FIGURE 3 is a view in side elevation partially cut away on a somewhat reduced scale of a television tube agitating table made in accordance with the present invention.

FIGURE 4 is a fragmentary top plan view of the tube agitating table and a television tube thereon showing the manner in which the tube is moved about in order to effect the abrading action.

Referring to the drawings and particularly to FIGURE 1, 19 indicates the glass envelope of a television tube which has been placed with its face down following the removal of the ion gun (not shown). The tube 10 is filled With Water 11, or some suitable liquid and a quantity of glass or ceramic marbles 12. or rounded pebbles are dropped through the neck 13 of the tube 10. By filling the tube 10 with the liquid 11, the marbles 12 are slowed in their descent through the tube and reach the interior of the tube face 15 without damaging it. After a suitable quantity of marbles 12 have been placed within the tube 10, the liquid 11 is poured off until only a very small quantity of it remains in the tube. A supply of a suitable abrasive in grit form such as, for example, a No. 24 grit is next poured through the neck of the tube It} upon the face 15 of the tube. With the desired amount of marbles 12 and abrasive within the tube, the tube may be placed upon an agitating table generally indicated at 16 in FIGURE 3. The table 16 consists of a top 17, supporting legs 18 and a movable rack 19 supported by the table top 17. The rack 19 is smaller than the table top 17 and is slidably received thereon.

The table top 17 is recessed as indicated at 20 and the rack 19 slides within the said recess. The table top 17 is also cut away as shown at 21 so that crank members 22 may be secured to the bottom of the rack 19.

The cranks 22 are driven through pulleys 23 and belts 24, 25 by means of a motor 26 secured to the table 16.

The tubes 10 are securely held upon the rack 19 by means of upstanding ring-like members 27. As the motor 26 is started and with the tubes 19 in place as shown in FIGURE 3, the tubes are caused to describe the somewhat circular motion shown in FIGURE 4 in dashed lines 28. As a result or" this motion, the abrasive material and marbles 12 are caused to slide with respect to the inner face 15 of the tube 10 and thereby grind away the materials deposited thereon. A slight amount of the glass envelope 10 may also be ground away at this juncture to provide a good surface to receive the new phosphor of the reconditioned tube.

it will be noted that the marbles or pebbles 12 which are placed within the tube envelope 16 are preferably of different sizes so that the radius 29 within the tube 16 as well as the flatter surfaces of the said tube will be cleaned.

After the abrading operation is finished the tube may be emptied of its abrasive and marbles and flushed out with water or any other suitable liquid. The finished roughed surface will provide an excellent base for deposition of the new phosphor.

From the foregoing it will be seen that there ha een provided a device and method for grinding the interior of television tubes without restorting to the use of acids and by means of which a uniform clean surface suitable for the reapplication of phosphors may be achieved.

The desired texture or roughness of the inner face 15 or" the tube 10 can be controlled by the proper selection of the abrasive in accordance with well known grinding techniques. The amount of material removed can be controlled by the length of time the tube is agitated upon the table.

Having thus fully described the invention, what is spa-5,909

claimed as new and desired to be secured by Letters References Cited in the file of this patent Patent of the United States, is: M

The method of grinding the interior of television tube UNITED STATES PATENiS envelopes comprising, the steps of placing the tube with 392,556 Harris Nov. 6, 1888 its wide viewing face in a horizontal position, filling the 5 563,757 Estabrook July 14, 1896 tube with a liquid, dropping a quantity of round marble- 856,619 Camp et a1 June 11, 1907 like members into the tube, pouring off all but a small 2,192,233 Mack Mar. 5, 1940 quantity of the fluid adding a quantity of abrasive mate- 2,440,931 Casson May 4, 1948 rial to the marble-like members, agitating the tube with a rotary motion until the tube is sufficiently ground, 10 FOREIGN PATENTS pourlng off the abrasive and marble-like members and 240,603 Great Britain Oct 8 1925 thereafter washing the interior of the tube. 

